Major work to dual two sections of the A47 in Norfolk is about to get under way in earnest - and will last for three years.

A sign has appeared on the A47 between Easton and North Tuddenham saying roadworks will begin on Monday, August 19.

The A47 between Easton and North TuddenhamThe A47 between Easton and North Tuddenham (Image: National Highways)

The work will see two new lanes created on the five-and-a-half mile stretch, while a separate project will involve the dualling of just over 1.6 miles of the route further east, between Blofield and North Burlingham.

The two schemes, along with a revamp of Thickthorn roundabout on the edge of Norwich, had been largely put on ice due to a long-running legal challenge by environmentalists trying to block the work.

While that challenge, by eco-campaigner Dr Andrew Boswell went on, National Highways, the government company behind the projects, was limited on what work it could do.

Dr Boswell had argued the government had acted unlawfully in allowing the road schemes because their cumulative impact on the environment had not been properly considered.

Dr Andrew BoswellDr Andrew Boswell (Image: Mike Page)

But the High Court and the Court of Appeal rejected his claim and his legal avenues were exhausted when the UK Supreme Court turned down his application in May.

While the case rumbled on, National Highways was restricted to work such as archaeological studies and re-routing utilities, rather than the actual dualling effort.

National Highways said the legal case had delayed the projects by months, adding millions to the cost.

There has been work done recently to move a gas line near North Burlingham and to install water tanks near Honingham - at a section of the road which has repeatedly flooded in recent months.

But the main work will now begin on the two dualling schemes, with construction due to go on until 2027.

On the stretch of road between North Burlingham and Blofield, work has recently been done to build a site office to manage the dualling scheme there.

The A47 schemes were originally announced in 2014, by then prime minister David Cameron, with £300m earmarked for Norfolk schemes, along with other improvements in Cambridgeshire.